It is well recognized that physical discomfort in the lower back of a seated person can often be relieved by elevating the feet on a footrest, footstool or ottoman. Furthermore, the serious complications from dependant edema from prolonged sitting may be reduced by elevating the feet on a footrest of some sort. People with short legs are also often in need of a footrest when seated in vehicles and ordinary chairs because their feet may not reach the floor, and excessive forces are consequently put on the thighs.
It is awkward to carry about an ordinary ottoman or footstool.
U.S. Pat. No. 4,462,636 issued Jul. 31, 1984 to Markson teaches a folding footstool including a platform for the feet to rest upon and a pair of vertical legs pivotally attached to opposite ends of the platform that fold up underneath the platform for portability. A pair of pivotally connected diagonal braces hold the legs open in a complex structure that prevents the legs from folding toward one another.
U.S. Pat. No. 4,437,413 issued Mar. 28, 1984 to O'Brian teaches a folding platform in which the legs also fold underneath the platform with a complex Sarrus linkage. In both inventions, the soiled platform surface upon which the feet have rested is exposed on an outer face of the folded package. The complex leg bracing mechanism is expensive and heavy. To be suitable for most applications, the folding footrest should be simple, light, compact and inexpensive.
The prior art designs are much stronger than is needed for merely holding the weight of the feet.